Rotary boring-drill.



H. R. HUGHES.

ROTARY BORING DRILL.

APPLICATION FILED FEB. 24, 1914.

L 1%,576, Patented Mar. 7,1916.

2 SHEETSSHEET l.

H. R. HUGHES.

ROTARY BORING DRILL. APPLICATION FILED FEB. 24,49l4.

Patented Mar. 7, 1-916 SHEET 2- HOW R. HUGHES, OF HOUSTON, TEXAS,ASSIGNOR T SHARP-HUGHES TOOI: COMEANY, 0F HOUSTON, TEXAS, A CORPORATIONOF TEXAS.

some? some-DRILL.

others skilled inthe art to which it appertains to make and use thesame.

This invention relates to rotary boring drills of the type that areequipped with rotatable cutters, and particularly to drills that haveinclined side cutterswhich revolve in planes converging in the head anda horizontally-disposed rotatable cutting device arranged between saidinclined side cuttersand extending diametrically across the head.

The main object of my present lnvention is to provide a rotary cutterdrill which comprises means for preventing the head of the drill fromcanting or wabbling sidewise in the hole when the cutters encounter orcome into alinement with a crevice'in the side wall of the hole.

Another object is to provide a'i-otary boring drill of novelconstruction that consists of a one-piece head equipped with a pair ofinclined rotatable side cutters arranged on opposite sides of atransversely disposed cutting device, and which is also provided with aplurality of. horizontally-disposed rollers arranged at a point abovesaid cutters for acting on the side wall of the hole.

Other objects and desirable features of my invention will be hereinafterpointed out.

Figure 1 of the drawings is a sideelevational view of a drillconstructed. in accordance. with my invention; Fig. 2 is a. bottom planview of said drill; Fig. 3 is a transverse sectional view of the drill;Fig. 4: is a transverse sectional view illustrating a slightmodification of my invention; and Figs. 5 to 8, inclusive, are detailviews illustrating various kinds of cutting surfaces that thehorizontally disposed steadying rollers on the head can be providedwith.

Briefly described, my improved drill con sists of a head provided withrotatable cutters that form a circular hole when the head is rotated,and means separate and distinct from said cutters which engagesthe sidewall of the hole in such a manner that the head cannot wabbleor movesidewise in the hole in case the cutters strike a crevice in the sidewall of the hole While I have Specification of Letters Eatent.

Patented Mar. '2, 191 .6. Application filed February 24, 1914. SerialNo. 820,674.

herein illustrated my invention embodied in i a drill thatis providedwith a pair of incllned side cutters arranged on opposite sides ofv ahorizontally-disposed cutting device that extends transversely acrossthe head, I"

do not wish it to be understood that my 1nvention is limited toa drillof this partic I ular'constructio-n as my broad idea consists inproviding the head of a rotary cutter drill with means which of itself,and entirely independent of the cutters, holds the head straight at alltimes when the drill is in operation, and prevents the head fromshiftlng laterally or from wabbling even when the cutters encounter acrevice in the side wall of therhole.

Referring to Fig. 1 of the drawings which illustrates the preferred formof my invention, A designates the head, preferably formed in one-piece,and provided at its upper end with a screw-threaded portion 1 forcooperating with a coupling sleeve 2 that secures the head to the drillstem 3, the head A also being provided with a screwtbreaded boss 4 orsome other suitable means for supporting a lubricant-holder 5. 'Thecutting. means of the drill consists of two' inclined side rollers Bwhich revolve in planes converging in the head, and a rotatable,horizontally-disposed cutting device that extends transversely acrossthe head between the inclined side rollers B, said transversely-disposedcutting device preferably consisting of a plurality of small cutters Cthat are rotatably mounted on a horizontal shaft 6 whose end portionsare supported in bearings 7 on the head A. The cutters C are preferablytapered, and are so arranged on the shaft 6 that they form acomparatively long cylindrical-shaped cutter which increases graduallyin diameter from its center toward its opposite ends, and thus forms asubstantially cone-shaped surface at the bottom of the hole which tendsto center the drill head and prevent it from wabbling in the hole.

A plurality of horizontally-disposed rollers D are rotatably mounted inthe head A at a point above the cutters B and C for engaging the sidewall of the hole so as to hold the drill steady when it is in operation,even when the cutters on the head encounter or come into alinement witha crevice m in the side wall of the hole. If it were not for the rollersD, the head of the drill would I wabble or movelaterally in the hole assoon would have nothing to work against to over come the side thrustsproduced by the action of the other side cutter on the side wall of thehole. Consequently, the rollers D insure the formation of a straighthole for said rollers bear against the side wall of the hole in such amanner that the head A is-held perfectly straight when the drill is inoperation. If the cutters B encounter a small crevice-a2 in the sidewall of the hole they will travel past said crevice without enteringsame, due to the fact that the rollers D are bearing against acylindrical portion of the side wall of the hole located above saidcrevice w. While the chief function of the rollers D is to steady thehead and prevent it from wabbling, said rollers can also be utilized tokeep the gage of the hole uniform and maintain a sufiicient clearancefor the drill. When the rollers D are used for this purpose as well asto steady the head, they are provided with cutting surfaces of somesuitable type which shear off the material at the side of the'hole; or,in other words, ream the side wall of the hole. The particular type ofcutting surfaces the rollers D are provided with is im material so faras my invention is concerned, and in Figs. 5 to 8 of the drawings 1 haveillustrated various kinds of cutting surfaces all of which areefi'icient,'the one shown in Fig. 5 consisting of straight chisel-teeth8, the one in F ig. 6 consisting of inclined chisel-teeth 8 the one inFig. 7 consisting of a spiral tooth 8 and" the one in 8 consisting ofsharp-pointed projections 55. The rollers D can either be set in smallpocle ets formed in the outer surface of the head A, or an annulargroove 9 can be formed in the head to receive the rollers D, the latterconstruction being preferably on account of the low cost of manufacture.As shown in Fig. 3, each of the rollers D is rotatably mounted on aspindle 10 whose upper end portion is seated in the part of the headthat forms the top wall of the annular groove 9, and whose lower endportion is screwed into the bottom wall of said annular groove, saidspindle being preferably provided with a bushing ll-on which the rolleris rotatably mounted, and washers 12 that bear against the top andbottom faces of the roller.

The cutters and the rollers D are kept thoroughly lubricated by'means ofa lubrieating medium which is supplied. continuously to the hearings ofsaid cutters and rollers through main luhricating duct 13 that leadsfrom; the lubricant-holder 5 nrrasve branch ducts it in the head whichlead to distributing ducts in the spindles and shafts on which thecutters and rollers are mounted, as indicated in broken lines in Fig. 3.

While I prefer to equip the drill with a horizontally-disposed cuttingdevice that extends transversely across the head, as shown in Fig. 3, itis not absolutely essential to the successful operation of the drillthat said cutting device extend clear across the head, for, if desired,said device could extend only part way across the head, as shown in Fig.4, wherein the reference character 7 designates a bearing at one side ofthe head which supports the outer end of the supporting shaft 6 for thecutters C, and the reference character 7 designates a bearing for theopposite end of said shaft that is located adjacent the center of thehead, a short sleeve 7 being arranged on said shaft between the bearing7 and the inner cutter C so as to prevent said cutters from movinglongitudinally of the shaft 6. At suitable points in the side of thehead vertically-disposed grooves or channels 15 are formed, as shown inFigs. 1 and 2, so as to provide ample clearance for the disintegratedmaterial that is flushed out of the hole by the wash-water which ispumped down through the drill stem and through the water-courses 16 inthe head, shown in broken lines in Figs. 2 and 8. While I prefer toprovide the drill with four rollers D arranged equal distances from eachother around the head, as shown in Fig. 2, l do not wish it to beunderstood that my invention is limited to a drill having thisparticular number and arrangement of steadying rollers for the sameresult could be accomplished in various other ways without departingfrom the spirit of my invention.

' Having thus described my invention, what claim as new and desire tosecure by Letters Patent is A rotary drill consisting of a head, a pairof inclined side cutters which revolve in planes that converge in thehead, a horizontally-disposed rotatable cutting device arranged betweensaid inclined side cutters, horizontallydisposed rollers arranged insaid head at a point above said cutters which act on the side wall ofthe hole, a lubricant holder and means for supplying the lubricant insaid holder to the bearings of said cutters, said cutting device andsaid rollers.

In testimony whereof ll hereunto adix my signature in the presence oftwo witnesses. this 16 day of February, 1914-.

' HQWVARD THU lFitn-esses:

L. it. Someone, G. litnno.

